Such hollow bodies are known per se and can be made and also manufactured as is described inter alia in EP 1 251 985 A1.
In this connection, such spherical hollow bodies have advantageous properties such as high mechanical strength, with a simultaneously reduced mass. Their outer surface is in particular likewise relatively large due to the spherical shape and even if the shell has a certain porosity, the outer surfaces are relatively planar and smooth, with a corresponding surface roughness.
However, these parameters are not sufficient for a number of applications.